The purpose of this proposal is to provide innovative and dedicated LC/MS/MS technology to the Clinical Pharmacology/ Analytical Chemistry Core (CPACC) of the University of North Carolina at Chapel Hill (UNC-CH) Center for AIDS Research (CFAR) and a group of researchers in the School of Pharmacy. It is estimated that CFAR related studies will utilize approximately 60% of the instrument time. The CPACC provides a centralized unit to facilitate the pharmacology and analytical studies of HIV/AIDS related clinical and basic science research at UNC-CH and collaborating CFAR institutions. Prior to the establishment of the CPACC in 1998, investigators struggled through their analytical and pharmacology needs by relying on the undependable timetables of unfunded colleagues or by contracting out the studies to costly private facilities. The success of the CPACC can be best exemplified by the outstanding score it received from peer reviewers during the CFARs five-year renewal proposal this year (The CFAR is virtually assured of . funding through 2006). This outstanding rating was given despite the fact the reviewers noted " this core is severely limited by a dedicated LC/MS facility". The lack of sufficient facilities at UNC-CH made it necessary for studies requiring LC/MS/MS technology to be carried out night and weekend via an arrangement with GlaxoSmithKline. Unfortunately, because these resources were limited a number of important projects had to be turned down by the CFAR. In addition to the CFAR, a small group of investigators from the School of Pharmacy will utilize 40% of the instrument time. This will serve to assure complete usage of the instrument from the moment of acquisition. Dr. Richard R. Tidwell (Director of the CPACC) will serve as PI of the proposal and will be responsible for all aspects of instrument maintenance and usage. Drs. Hall and Kashuba will prioritize CPA CC use and Dr. Gary Pollack will prioritize use by School of Pharmacy scientists. The instrument will be housed in newly renovated space in the School of Pharmacy.